Feedback regulation of m6A modification creates local auxin maxima essential for rice microsporogenesis

Abstract

N⁶-methyladenosine (m⁶A) RNA modification and its effectors control various plant developmental processes, yet whether and how these effectors are transcriptionally controlled to confer functional specificity so far remain elusive. Herein, we show that a rice C2H2 zinc-finger protein, OsZAF, specifically activates the expression of OsFIP37 encoding a core component of the m⁶A methyltransferase complex during microsporogenesis in rice anthers. OsFIP37, in turn, facilitates m⁶A modification and stabilization of an auxin biosynthesis gene OsYUCCA3 to promote auxin biosynthesis in anthers. This elevates auxin levels coinciding with upregulation of an auxin response factor OsARF12 that positively controls OsZAF, thus creating a positive feedback circuit whereby OsFIP37 is continuously activated for local auxin production. Our findings suggest that OsZAF-dependent feedback regulation of m⁶A modification is integral to local auxin biosynthesis and signaling in anthers, which facilitates the timely generation of auxin maxima required for male meiosis in rice.